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The Henry Draper Extension Charts: A catalogue of accurate positions, proper motions, magnitudes and spectral types of 86933 stars
The Henry Draper Extension Charts (HDEC), published in the form offinding charts, provide spectral classification for some 87000 starsmostly between 10th and 11th magnitude. This data, being highlyvaluable, as yet was practically unusable for modern computer-basedastronomy. An earlier pilot project (Roeser et al. 1991) demonstrated apossibility to convert this into a star catalogue, using measurements ofcartesian coordinates of stars on the charts and positions of theAstrographic Catalogue (AC) for subsequent identification. We presenthere a final HDEC catalogue comprising accurate positions, propermotions, magnitudes and spectral classes for 86933 stars of the HenryDraper Extension Charts.
| A photometric study of BL Herculis
Photometric observations of the prototype variable BL Her are described.The reddening, metallicity, temperature, and surface gravity of the starare determined. A Baade-Wesselink analysis is made to determine theradius and distance to the variable. The mass of the star is determinedto be 0.75 solar, placing it in the range of RR Lyrae variables. Themetallicity of +0.20, however, is greater than that of any known RRLyrae variable.
| Observational studies of Cepheids. II - BVRI photometry of 112 Cepheids
Over 4000 differentially determined photoelectric BVRI observations andthe resulting light curves are presented for 112 Cepheids accessiblefrom Northern Hemisphere observatories. The internal precision of thesedata is better than + or - 0.01 mag, and the accuracy of transformationto the Johnson BVRI system is nearly as good.
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Pozíciós és asztrometriai adatok
| Csillagkép: | Herkules |
| Rektaszcenzió: | 18h01m02.10s |
| Deklináció: | +19°00'26.3" |
| Vizuális fényesség: | 9.627 |
| RA sajátmozgás: | 8.8 |
| Dec sajátmozgás: | 2.9 |
| B-T magnitude: | 9.838 |
| V-T magnitude: | 9.645 |
Katalógusok és elnevezések:
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